US2991834A - Cutting tool - Google Patents

Description

July 11, 1961 Filed Aug. 21, 1957 T. A. KENNARD CUTTING TOOL Sheets-Sheet 1- INVENTOR.

7/70/7704 A. Ken/70rd July 11, 1961 1-. A. KENNARD CUTTING TOOL Filed Aug. 21, 1957 -vsb iya 2 Sheets-Sheet 2 United States Patent- 2,991,834 CUTTING TOOL Thomas A. Kennard, Box 723, Jennings, La. Filed Aug. 21, 1957, Ser. No. 679,332 Claims. (Cl. 166- 55.7)

This invention relates to well tools and more particularly to tools for cutting off and removing from a well an upper section of a string of pipe and to an assembly for anchoring tools or the like in a well.

It is an object of this invention to provide a new and improved tool for removing fish from a well with a single tool which cuts and washes away interfering material, then cuts free a section of pipe and then removes the cut section from the well; all in one run.

Another object is to provide a tool for removing fish from a well in which the fish maybe released at any time and after releasing the fish the tool is ready for reuse and may be moved to another location.

Another object is to provide a tool which, if the fish cannot be pulled after cutting, can be released and a cut made at a shallower depth; then when the fish is pulled the tool can be released and anchored to the stuck fish to pull all cuts out of the hole the same trip.

Another object is to provide a cutting tool for well pipe in which the tool is anchored to the pipe during the cutting action and in which the tool may be freed from the pipe at any time without damage to the tool.

Another object is to provide a cutting tool for well pipe in which the cutting knives may be retracted at any time and held in an out-of-the-way position to permit movement of the tool in the pipe.

Another object is to provide a cutting tQol for well pipe employing a slip assembly for anchoring the tool to the pipe in which downward movement of the' string from which the tool is suspended moves the slips into an inoperative position to permit moving the tool upward.

Another object is to provide a setting assembly for anchoring a tool to a well pipe including a slip assembly on a mandrel in which movement of the mandrel downward relative to the slip assembly after the setting assembly has anchored the tool to a pipe renders the an choring assembly inoperative to permit release of the pipe by the tool. 1

Other objects, features and advantages of this invention will be apparent from the drawings, specification and claims.

In the drawings wherein like referenced numerals indicate like parts:

FIGS. 1, 2, and 3 are schematic views in section of a tool constructed in accordance with this invention and showing in FIG. 1 the position of the parts as the tool is run into the hole, in FIG. 2 the slip assembly in the process of being anchored, and in FIG. 3 the tool anchored in a pipe and cuttingfree an upper section of pipe; and

FIGS. 4A, 4B, and 4C are continuation views partly in longitudinal elevation and partly in longitudinal cross section of a preferred form of this invention.

The tool illustrated in the drawings includes a mandrel indicated generally at which extends the full length of the tool and carries thereon a sleeve indicated generally at 11. Carried by one of the mandrel and sleeve, preferably the sleeve as illustrated, are a plurality of cutters or knives 12 (FIG. 4B) which are'in retracted position with the mandrel and sleeve in one telescoped position. The cutters are extended .by a resiliently loaded actuator 13 when the mandrel and sleeve are in another relative telescoped position. At the upper end of the tool (FIG. 4A) there is provided a settin g'asse nbly in- 2. dicatcdgenerally at 1 4 for anchoring the tool to. a fish. The setting assembly provides a stop limiting. movemen-t of the sleeve 11 to cause change of the relative telescoped position between the mandrel and sleeve upon raising of the mandrel after the setting assembly has secured the tool to a pipe. As will be explained in detail below the setting assembly may be released at will of the operator to permit changing the position of the tool in the fish or completely withdrawing the tool. The mandrel 10 is preferably hollow as shown to provide a fluid passageway to maintain circulation and washv interferi'ng material away from the fish; The lower. end of. the tool is provided with a bit indicated generally at 15 for cutting away interfering material to permitthe tool to reach the fish.

The mandrel 10 includes. an upper section 16 and a lower section 17. Each of sections 16 and 17 is tubular in form to provide a bore 18 extending through the mandrel for maintaining circulation through the tool. The mandrel 10 is suspended from head sub 19; which is the lower end of a conventional string of pipe used in running tools of this type. i i

The setting assembly 14 is preferably carried on the upper section 16. The setting assembly includes a slip carrier 21 surrounding upper mandrel section 16 aiid slidably and rotatably mounted'thereon. A plurality of drag springs 22 are mounted on the slip carrier 21 extend between carrier 21 and the drag spring cage23 which is also slidably and rotatably mounted'on the upper mandrel section :16. The drag springs 22 engage the wall of a pipe into which the tool is and frictional-1y resist movement of the slip carrier relative to this pipe. This permits relative shifting between the slip carrier. and mandrel under the control of the operator atI-the surface. Depending from the slip carrier are a plurality offslip fingers 24. The lower end of fingers 24 are provided with teeth 23 for gripping the pipe or fish to be removed'whe n the slip fingers are expanded.

For purposes of selectively. expanding th slip fingers 24 cone 26 is provided. Cone '26 isrotatably and slidably mounted on the upper mandrel section 16 and iscoufined between theupper end of the sleeve 11 andfa shoulder 27 on the upper mandrel section 16. It will be readily apparent that moving the cone '26 behind the slip fingers 25 will force the ,slip fingers 25 outward and into engagement with the wall of the fish.

Shoulder 27 also acts as a jar 'knocker to drive the cone from behind the slips when disengaging thetodl from a pipe. i

The slip fingers are held in an out-of-.the=way position during withdrawal of the tool and: are moved into a position to be engaged by the cone on setting of the tool by a short sectionof complementary threads 28 on the slip finger and the upper mandrel section 16. The threads are raised on both the slip fingers and mandrel section and do not interfere with the operation of the setting assembly except when they are engaged. 'Ihe upper flanks 28a of the threads on the mandrel and the complementary lower flanks 28b of the threads on the slip fingers are inclined slightly from a plane perpendicular tothe axis of the mandrel. These flanks provide stops which prevent the slip fingers moving downwardly after the thread system has been engaged except upon rotation of the mandrel relative to the slip fingers. On the other hand the upper flanks 28c of the thread on' the slip fingers and the lower flanks 28a of themand re l threads are inclined at a substantial angle from snails perpendicular to the axis of the mandrel to permit this threads of the slip fingers .to slide upward over threads on the mandrel. Thus on going in the hole the slip carrier will always move relatively upwardly with an inclined flank 28e or jump thread at the lower end of the thread system which prevents engagement of the thread system as the mandrel moves upwardly relative to the slip carrier until all threads on the mandrel have passed the jump thread. This permits all threads of the thread system to engage simultaneously. This jump thread system insures that all of the threads of the system are engaged and there is no danger of pulling the mandrel up through the slip fingers. Also the operator will know that only a predetermined number of revolutions are necessary to disengage the mandrel and slip fingers. Once the mandrel has been turned through this number of revolutions the slip fingers are disengaged and have been moved downwardly into a position to be engaged by cone 26 as the mandrel is raised.

Referring now particularly to FIG. 4B, the sleeve 11 includes an upper splined section 29 and a lower cutter body section 31. The lower mandrel section 17 has at its upper end a splined nut 32 which cooperates with the splined sleeve section 29 to impart rotation from the mandrel to the sleeve. The splined portion 29a of sleeve 29 terminates at its upper and lower ends at stops 29b and 29:: respectively which are engaged by the splined jar nut 32 to limit relative movement of the sleeve and mandrel. With the nut 32 in engagement with the stop 290, the knives 12 are in their retracted position. With the nut 32 in engagement with the upper stop 29b the knives are in operating position. A direct pull may be imparted from nut 32 to cone 26 which rests on the top of the splined sleeve section to drive the cone firmly home behind the slip fingers.

The cutter body 31 is slotted as at 33. Knives 12 are pivotally mounted on the cutter body in slots 33 for radial movement into engagement with a pipe to be cut. Relatively weak knife springs 34 bias each of the knives 12 toward fully retracted position.

As the mandrel moves upwardly in sleeve 11 expansion spring 35 for the sleeve 11 is collapsed. This spring returns the sleeve and mandrel to their relative telescoped position as viewed in FIGS. 4A, 4B, and 40 upon lowering of the mandrel relative to the sleeve.

A resiliently urged actuator is provided for moving the knives radially into contact with the pipe to be cut. Preferably the resilient means is provided by a feeder spring 36.

To insure that the spring 36 is inoperative to force the actuator 13 into engagement with the cutters 12 when the tool is not anchored in the pipe, there is provided an actuator release which prevents operation of the actuator until the mandrel is moved upwardly relative to the sleeve from the position shown in FIG. 4B. In the form of the invention illustrated the actuator release is provided by a shoulder 37 on the mandrel which engages an actuator release plug 38 on the actuator and prevents upward movement of the actuator. As the mandrel is pulled upwardly relative to the sleeve the shoulder 37 is moved into an out-of-the-way position and the spring urges the actuator 13 behind the cutters 12. The wedge 13a on the actuator forces the cutters radially into engagement with the pipe to be cut.

It will be noted that the feeder spring 36 is supported on a lifting nut 39 secured to the lower end of the mandrel 10. Thus the force behind the knives can be varied by controlling the relative positions of the mandrel and sleeve. On the other hand the positive stop provided by contact of the spline nut 32 with the upper stop 29b in the spline portion of the sleeve will limit the amount of force which can be applied to drive the cutters radially.

Depending from the lifting nut 39 is a tail pipe or pack off tube 41 which has a sliding seal with the pack ofi sub 42. Sub 42 depends from the cutter body 31. The pack off sub 42 carries at its lower end the bit 15. With this arrangement a positive seal is provided for forcing fluid circulated through the mandrel out the lower end of the bit for a jetting and washing action on the material interfering with the movement of the tool into position within the fish.

Operation of the tool is illustrated in FIGS. 1, 2, and 3. In FIG. 1 the tool is being run in the hole. The slip as sembly, dueto the friction of drag springs 22, is at its uppermost position and abutting the head sub 19. In this position the cone 26 is removed from the slip fingers 24 and the slip fingers do not interfere with the running of the tool. When the tool reaches the fish it may be rotated to permit bit 15 to drill through interfering material. Drilling fluid may be circulated through the tool to wash away cuttings in the usual manner.

After the tool is lowered into the fish the desired distance the pipe string on which the tool is mounted is raised. This condition is illustrated in FIG. 2. As the mandrel moves upward the drag springs 22 hold the slip assembly against movement and the mandrel moves upward relative to the slip assembly until the thread system 28 engages. It will be recalled that jump thread 28c holds the thread system out of engagement until all threads are in position to engage and then permits the threads to engage. From FIG. 2 it will be noted that at this time the slip segments and the cone are still not in engagement. To move the slips into a position to be engaged by the cone. the operator rotates the drill string counterclockwise a sufiicient number of turns to move the slip assemblydownward relative to the mandrel until the thread system 28 is disengaged. At this time the cone 26 will be positioned just below the slip segments. If desired the design may be such that initial engagement is provided between the slip segments and the cone. In either case as soon as the thread system 28 is disengaged the operator again raises the string to raise the mandrel and force the cone behind the slip segments. The slip fingers are driven into the wall of the pipe to anchor the tool relative to the pipe. Continued upward movement is then exerted on the mandrel and the mandrel will move upwardly through the sleeve 11 until the mandrel and sleeve are in the relative telescoped position illustrated in FIG. 3. At this time the actuator release 37 will be in out-of-the-way position and the feeder spring 36 will move the actuator behind the cutters and force them radially into the wall of the pipe to be cut. With the tool in the position illustrated in FIG. 3, rotation of the tool will rotate the knives and the fish will be cut in two as illustrated in FIG. 3.

After the cut has been completed the spring may be raised to bring the tool and the fish to the surface.

If after the tool is engaged in the pipe and cut is commenced, it is desired to release the fish this may be easily accomplished. One instance in which it would be desired to release the fish is when the fish cannot be pulled. In this case it would be desirable to be able to release the fish and raise the tool to a shallower depth and make an additional cut. This is possible with the tool of this invention as it may be released without damage merely by lowering the mandrel through the sleeve to the posi tion shown in FIG. 2. With the tool in this position the spline nut 32 engages stop 29c and upward force on the cone 26 is removed. Then by jarring down on the mandrel the mandrel shoulder 27 (FIG. 4A) will drive the cone out from under the slip fingers.

After the cone is jarred free, further lowering of the mandrel relative to the slip assembly will cause the threads on the mandrel to pass through the threads on the slip fingers and the parts of the tool will again assume the position illustrated in FIG. 1. The tool may then be raised and the parts will then assume the position illustrated in FIG. 2 with the thread system engaged. However as the cone is not in engagement with the slip fingers the tool may be raised to a shallower depth and reset in the manner above explained. A second cut may then be made and the fish pulled free. When the top section of the fish is pulled free it may be released and the tool run in again to the position of approximately the first cut and the tool again set in the section of pipe above the first cut but below the second out. As the mandrel is lifted this time the fish may come free; if not another section of fish is cut oif and the operation repeated until the fish is freed to the desired depth. Then the tool may be pulled to the surface while secured to the lowermost fish bringing with it all of the preceding cuts.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes may be made within the scope of the appended claims without departing from the spirit of this invention.

What is claimed is:

1. A pipe cutter comprising, a tubular mandrel adapted to be secured to the lower end of a string of pipe, an outer sleeve mounted on the mandrel for limited sliding movement, resilient means urging the sleeve upward relative to the mandrel, cutters carried by the sleeve, means urging the cutters radially outward when the sleeve and mandrel are moved relative to each other against said resilient means, a cone rotatably and slidably positioned on the mandrel at the upper end of the sleeve, a slip assembly including a slip carrier slidably mounted on the mandrel above the cone and having a plurality of slip fingers depending from the carrier which when expanded by the cone engage the wall of a pipe in which the assembly is run to anchor the assembly, drag springs on the slipassembly, a short section of threads on the slip assembly and mandrel which when engaged hold the slips above the cone and when the mandrel is screwed upward through the slip assembly releases the slips for engagement with the cone, said threads ineffective to prevent the slips moving away from the cone, and means eifective upon lowering of the mandrel for forcing the cone out of engagement with the slip assembly.

2. A setting assembly for a well tool comprising, a tubular mandrel adapted to be secured to the lower end of a string of pipe, a cone rotatably and slidably mounted on the mandrel, a slip assembly including a slip carrier slidably mounted on the mandrel above the cone having a plurality of slip fingers depending from the carrier and when expanded by the cone engaging the wall of a pipe in which the assembly is run to anchor the assembly, drag springs on the slip assembly, and a short section of threads on the slip assembly and mandrel which when engaged hold the slip fingers above the cone and when the mandrel is screwed upward through the slip assembly releases the slip fingers for engagement with the cone.

3. A setting assembly for 'a well tool comprising, a tubular mandrel adapted to be secured to the lower end of a string of pipe, a cone rotatably and slidably mounted on the mandrel, a slip assembly including a slip carrier slidably mounted on the mandrel above the cone having a plurality of slip fingers depending from the carrier and when expanded by the cone engaging the wall of a pipe in which the assembly is run to anchor the assembly, drag springs on the slip assembly, a short section of threads on the slip assembly and mandrel which when engaged hold the slip fingers above the cone and when the mandrel is screwed upward through the slip assem- 6 bly releases the slip fingers for engagement with the cone, and means elfective upon lowering of the mandrel for forcing the cone out of engagement with the slip fingers.

4. A setting assembly for a well tool comprising, a mandrel, a cone mounted on the mandrel, a slip carrier slidably mounted on the mandrel and having a plurality of slip fingers depending from the carrier and when spread by the cone engaging the wall of a pipe and anchoring the tool, drag springs on the slip carrier, a short section of co-acting threads on the slip fingers and mandrel, the flanks of said threads formed at an angle permitting the threads of the slip fingers to move over the threads on the mandrel when the mandrel is moved downward through the slip fingers, said threads when engaged preventing the mandrel from moving upward through the slip fingers to hold the slip fingers out of engagement with the cone, said threads released to permit engagement of the fingers and cone by relative rotation of the mandrel and slip fingers.

5. A pipe cutter for wells comprising, a tubular mandrel adapted to be secured to the lower end of a string of pipe, a concentric sleeve non-rotatably carried by the lower end of the mandrel and mounted for limited sliding movement, resilient means urging the sleeve toward the upper end of the mandrel, cutters mounted on the sleeve for radial movement, relatively weak resilient means urging the cutters in one radial direction, an actuator mounted in an annulus between the mandrel and sleeve and having wedge means cooperable with the cutters to urge them radially, relatively strong resilient means biasing the actuator toward the cutters to urge the cutters in the other radial direction, an actuator release carried by the mandrel effective to hold the actuator out of engagement with the cutters when the mandrel is at the lower end of its travel relative to the sleeve and releasing the actuator as the mandrel moves upward relative to the sleeve, a cone rotatably and slidably positioned on the mandrel at the upper end of the sleeve, a slip assembly including a slip carrier slidably mounted on the mandrel above the cone and having a plurality of slip fingers depending from the carrier which when expanded by the cone engage the wall of a pipe in which the assembly is run to anchor the assembly, drag springs on the slip assembly, a short section of threads on the slip assembly and mandrel which when engaged hold the slips above the cone and when the mandrel is screwed upward through the slip assembly releases the slips for engagement with the cone, said threads ineffective to prevent the slips moving away from the cone, and means effective upon lowering of the mandrel for forcing the cone out of engagement with the slip assembly.

References Cited in the file of this patent UNITED STATES PATENTS 1,867,289 Ventresca July 12, 1932 1,941,703 Martois Jan. 2, 1934 1,992,933 Baker et al. Mar. 5, 1940 2,202,986 Ellis June 4, 1940 2,203,011 Ellis et al. June 4, 1940 I 2,604,945 Page July 29, 1952 2,623,593 Pennington et al Dec. 30, 1952 2,659,434 Osmun Nov. 17, 1953 2,665,765 Baker Jan. 12, 1954

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